Description

Dual-bridge (DB) LLC reso-nant converter for wide input applications. The topology is an in-tegration of a half-bridge (HB) LLC circuit and a full-bridge (FB) LLC circuit. The fixed-frequency pulsewidth-modulated (PWM) control is employed and a range of twice the minimum input volt-age can be covered. Compared with the traditional pulse frequency modulation (PFM) controlled HB/FB LLC resonant converter, the voltage gain range is independent of the quality factor, and the mag-netizing inductor has little influence on the voltage gain, which can simplify the parameter selection process and benefit the design of magnetic components as well. Over the full load range, zero-voltageswitching (ZVS) and zero-current switching (ZCS) can be achieved for primary switches and secondary rectifier diodes, respectively. Detailed analysis on the modulation schedule and operating princi-ple of the proposed converter is presented along with the converter performance. Finally, all theoretical analysis and characteristics are verified by experimental results from a 120-V to 240-V input 24 V/20 A output converter prototype.